Struct SteinerTreeInGraphs 

pub struct SteinerTreeInGraphs<G, W> { /* private fields */ }

The Steiner Tree in Graphs problem.

Given a weighted graph G = (V, E) with edge weights w_e and a subset R ⊆ V of required terminal vertices, find a subtree T of G that includes all vertices of R and minimizes the total edge weight Σ_{e ∈ T} w(e).

Representation

Each edge is assigned a binary variable:

• 0: edge is not in the tree
• 1: edge is in the tree

A valid Steiner tree requires:

• All terminal vertices are connected through selected edges
• Selected edges form a connected subgraph (optimally a tree)

Type Parameters

• G - The graph type (e.g., SimpleGraph)
• W - The weight type for edges (e.g., i32, f64)

Example

use problemreductions::models::graph::SteinerTreeInGraphs;
use problemreductions::topology::SimpleGraph;
use problemreductions::{Problem, Solver, BruteForce};

// Path graph 0-1-2-3, terminals {0, 3}
let graph = SimpleGraph::new(4, vec![(0, 1), (1, 2), (2, 3)]);
let problem = SteinerTreeInGraphs::new(graph, vec![0, 3], vec![1, 1, 1]);

let solver = BruteForce::new();
let solution = solver.find_witness(&problem).unwrap();
// Optimal: select all 3 edges (the only path from 0 to 3)
assert_eq!(solution, vec![1, 1, 1]);

Implementations

impl<G: Graph, W: Clone + Default> SteinerTreeInGraphs<G, W>

pub fn new(graph: G, terminals: Vec<usize>, edge_weights: Vec<W>) -> Self

Create a SteinerTreeInGraphs problem from a graph, terminals, and edge weights.

Panics

Panics if edge_weights.len() != graph.num_edges() or any terminal index is out of bounds.

pub fn graph(&self) -> &G

Get a reference to the underlying graph.

pub fn terminals(&self) -> &[usize]

Get the terminal vertices.

pub fn edges(&self) -> Vec<(usize, usize, W)>

Get all edges with their weights.

pub fn set_weights(&mut self, weights: Vec<W>)

Set new weights for the problem.

pub fn weights(&self) -> Vec<W>

Get the weights for the problem.

pub fn is_weighted(&self) -> bool

where W: WeightElement,

Check if the problem uses a non-unit weight type.

pub fn is_valid_solution(&self, config: &[usize]) -> bool

Check if a configuration is a valid Steiner tree.

impl<G: Graph, W: WeightElement> SteinerTreeInGraphs<G, W>

pub fn num_vertices(&self) -> usize

Get the number of vertices in the underlying graph.

pub fn num_edges(&self) -> usize

Get the number of edges in the underlying graph.

pub fn num_terminals(&self) -> usize

Get the number of terminal vertices.

Trait Implementations

impl<G: Clone, W: Clone> Clone for SteinerTreeInGraphs<G, W>

fn clone(&self) -> SteinerTreeInGraphs<G, W>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<G: Debug, W: Debug> Debug for SteinerTreeInGraphs<G, W>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de, G, W> Deserialize<'de> for SteinerTreeInGraphs<G, W>

where G: Deserialize<'de>, W: Deserialize<'de>,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<G, W> Problem for SteinerTreeInGraphs<G, W>

where G: Graph + VariantParam, W: WeightElement + VariantParam,

const NAME: &'static str = "SteinerTreeInGraphs"

Base name of this problem type (e.g., “MaximumIndependentSet”).

type Value = Min<<W as WeightElement>::Sum>

The evaluation value type.

fn variant() -> Vec<(&'static str, &'static str)>

Returns variant attributes derived from type parameters.

fn dims(&self) -> Vec<usize>

Configuration space dimensions. Each entry is the cardinality of that variable.

fn evaluate(&self, config: &[usize]) -> Min<W::Sum>

Evaluate the problem on a configuration.

fn num_variables(&self) -> usize

Number of variables (derived from dims).

fn problem_type() -> ProblemType

Look up this problem’s catalog entry.

impl ReduceTo<ILP> for SteinerTreeInGraphs<SimpleGraph, i32>

type Result = ReductionSTIGToILP

The reduction result type.

fn reduce_to(&self) -> Self::Result

Reduce this problem to the target problem type.

impl<G, W> Serialize for SteinerTreeInGraphs<G, W>

where G: Serialize, W: Serialize,

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl DeclaredVariant for SteinerTreeInGraphs<SimpleGraph, One>

impl DeclaredVariant for SteinerTreeInGraphs<SimpleGraph, i32>